Mechanical coding between a battery pack and an electrical tool

ABSTRACT

The invention relates to a plug-in battery pack ( 1 ) for an electric tool, comprising a mechanical coding ( 16 ) of a coding system ( 30 ), which co-operates with a mechanical counter-coding of the coding system that is assigned to the electric tool, the coding extending in the plug-in direction of the battery pack. According to the invention, the coding comprises at least one recess ( 17 ), which co-operates with a projecting part ( 40 ) on the tool side that forms the counter-coding, said recess and part being on opposite sides. The invention also relates to a corresponding coding system.

CROSS-REFERENCE

The invention described and claimed hereinbelow is also described inPCT/EP2006/050008, filed on Jan. 3, 2006 and DE 10 2005 008 036.7, filedon Feb. 22, 2005. This German Patent Application, whose subject matteris incorporated here by reference, provides the basic for a claim ofpriority of invention under 35 U.S.C. 119 (a)-(d).

BACKGROUND OF THE INVENTION

The invention relates to a plug-in battery pack for an electrical tool,having a mechanical coding of a coding system for a cooperation with amechanical counterpart coding of the coding system associated with theelectrical tool, in which the coding extends in the insertion directionof the battery pack.

In order to assure the attachment of the correct battery pack to theelectrical tool, it is known to use mechanical coding systems that onlypermit the battery pack to be inserted and electrically connected if thebattery pack has a coding that corresponds to the counterpart coding ofthe electrical tool. The prior coding designs, however, have thedisadvantage that with the exertion of sufficiently intense insertionforces, in particular improperly high insertion forces, the mechanicalcoding elements can be destroyed or “forced” due to lateral deflectionso that it is also possible for incorrect battery packs to be insertedinto the receiving shaft of the electrical tool. In the context of thisapplication, the term “battery pack” is understood to be a rechargeablebattery pack composed of a plurality of cells that supplies the energyfor the operation of the electrical tool and is accommodated inreplaceable fashion in a chamber or the like of the electrical tool. Thebattery pack is attached to the electrical tool by being plugged in orinserted. If the energy of the battery pack runs out, then the batterypack can be removed and placed in a charging station. If there are anumber of battery packs available, it is then possible to remove thedischarged battery pack from the electrical tool and replace it with acharged one. When switching battery packs or when reattaching therecharged battery pack, preventing an incorrect battery pack from thenbeing attached to the electrical tool—which could occur particularlywhen using a number of different battery packs for different electricaldevices—requires a secure and essentially non-manipulable coding system.Such a coding system should also prevent the use of incorrect batterypacks that should not be attached to the electrical tool.

SUMMARY OF THE INVENTION

The present invention offers the advantage that improper manipulations,i.e. the attachment of incorrect battery packs to the electrical tool,are prevented by virtue of the fact that the coding has at least onerecess that cooperates on opposite sides with at least one projection onthe tool that constitutes the counterpart coding. Accordingly, thecounterpart coding that is associated with the electrical tool iscomprised of at least one projection, the battery pack has at least onecorresponding recess, and opposite sides of the recess cooperate withthe projection when the battery pack is being inserted into theelectrical tool. If an incorrect battery pack is used in which thecoding and the counterpart coding do not precisely correspond to eachother in the correct way, then because of the non-matching dimensions,the projection rests against the outer edge or outer edges of therecess. If an improperly high level of force is then neverthelessexerted in an attempt to push the battery pack in, then the projectionis deflected slightly in the lateral direction, for example, because awall surface of the recess acts on it laterally with the result that theend surface of the projection comes to rest against the correspondingopposite outer edge of the recess and further insertion is blocked. The“forcing” explained above in connection with the prior art is thereforenot possible. Only an extremely violent insertion could possiblynevertheless force the battery pack into the electrical tool, but thiswould be accompanied by a mechanical destruction of large regions sothat the entire arrangement would become unusable, for example due tobreakage of contacts or cracking of housing zones or the like. The usertends to refrain from such an improper action, thus assuring that onlycorrect battery packs will be attached to the electrical tool.

According to a modification of the invention, the recess has at leasttwo wall surface regions situated opposite each other in accordance withthe thickness of the projection. When the battery pack is being attachedto the electrical tool, the projection travels between these two wallsurface regions, i.e. the two wall surface regions, embrace theprojection and guide it as it passes between them. It is therefore clearthat a lateral bending of the projection would cause a stoppage thatprevents the insertion movement of the battery pack and even powerfulforces would not be able to overcome this stoppage.

It is advantageous if the recess is a circumferentially closed recess.This is understood to mean a recess whose recess edge describes anintrinsically closed, loop-shaped line. Alternatively, it is alsopossible for the recess to be a recess that is open at the edge, i.e. itis accessible—from the side—through at least one opening; in otherwords, its edge is not an intrinsically closed, loop-shaped line, butinstead forms an open U-shape, for example.

It is also advantageous if the recess has a single-cornered,multi-cornered, arc-shaped, and/or circular outline structure. Theprojection is correspondingly provided with the same outline structure,thus permitting a definite association between the projection and therecess. This prevents incorrect rotational positioning of the batterypack and the electrical tool.

The recess is preferably embodied in the form of a cylindrical recess,i.e. its wall surfaces extend parallel to one another. They do not taperdown toward the bottom of the recess, but instead extend parallel to theinsertion direction. The term “cylindrical” is correspondinglyunderstood to mean that an imaginary line extending from the recess edgeto the recess bottom is shifted parallel to itself along an arbitraryclosed or non-closed curve that defines the cylinder contour so that therecess does not have any surfaces, wall sections, or the like thatextend obliquely in relation to the insertion direction.

According to a modification of the invention, the recess is situated inthe vicinity of electrical contacts of the battery pack. It is thereforeadvantageous if the blocking action of non-matching coding elements isexerted in the vicinity of the electrical contacts and thereforereliably prevents a contacting of the battery pack with thecorresponding connections of the electrical tool.

In particular, the recess can be situated between at least twoelectrical contacts of the battery pack. This likewise achieves theabove-mentioned advantages.

According to a modification of the invention, the recess is situated ona contact dome of the battery pack. This contact dome supports thecoding on the one hand and on the other hand, also supports theelectrical contact elements for producing an electrical connectionbetween the battery pack and the electrical tool through the insertionof the battery pack into the electrical tool.

Preferably, the recess and/or the contact dome is/are situatedeccentrically in relation to the center of the base surface of thebattery pack, thus preventing incorrect rotational positioning and thuspermitting the battery pack to be attached to the electrical tool inonly a single position.

In order to create a multitude of permutations, i.e. in order to permitcertain battery packs to be plugged into an electrical tool but toprevent other battery packs, possibly equipped with the same electricalparameters, from being connected to a particular electrical tool, atleast one coding rib extends out from the wall of the recess. Inaddition to the coding unit already comprised by the projection and therecess, the coding rib provides an additional, improved coding measure.This is particularly the case if the coding rib extends out from thewall of the recess at a certain positions out of a plurality ofdifferent positions in order to produce various permutations.Accordingly, there are battery packs with coding ribs that differ fromother battery packs with coding ribs in that the coding ribs of thevarious battery pack embodiments are situated in different positionsinside the recess, extending out from the wall of the recess so thatthis provides a differentiation between permutations. These differentpermutations are naturally implemented only when the projection has acorresponding shape—in particular an outline structure—that takes intoaccount the coding rib or coding ribs.

According to a modification of the invention, at least one pair ofcoding ribs extends out from the wall of the recess, whose coding ribsare situated opposite from each other so that they overlap at leastpartially. Correspondingly, a pair of coding ribs is composed of twocoding ribs that are situated opposite from and spaced apart from eachother so that the projection can slide between their end surfaces as thebattery pack is inserted into the electrical tool. In this case, it isnot necessary for the two coding ribs—viewed transversely to theinsertion direction—to be aligned with each other, i.e. for them to havethe same width as each other and be situated in an aligned position onebehind the other (aligned end surfaces), instead, it is also possible touse coding ribs that do not have the same width and comprise a pair ofcoding ribs and/or are situated offset from each other. But the offsetis not so great as to leave a lateral open space between them; instead,the end surfaces overlap each other at least partially.

According to a modification of the invention, the recess, which is openat the edge, is adjoined by at least one outside wall surface situatedopposite from a region of the projection. Correspondingly, at least oneregion situated outside the open-at-the-edge recess is also used for thecoding system in that the projection extends not only inside theopen-at-the-edge recess, but also reaches into the lateral opening ofthe recess and extends so that it faces an outer wall surface situatedthere, which adjoins the recess. This increases the variety ofpermutations and also increases the security of the permutations systembecause of the larger-area embodiment of the elements.

Finally, the invention relates to a coding system for an electrical toolprovided with a plug-in battery pack, in particular according to one ormore of the preceding embodiments and modifications; the battery packhas a mechanical coding, the electrical tool has a mechanicalcounterpart coding, and the coding and counterpart coding extend in theinsertion direction; the coding is embodied as at least one recess, thecounterpart coding is embodied as at least one projection, and thecoding and counterpart coding are matched to each other in aform-fitting fashion and engage in each other when the battery pack isin the inserted position. In this case in particular, the projectioncooperates with opposing sides of the recess.

Several exemplary embodiments of the invention are depicted in thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a coding of a plug-in battery pack foran electrical tool,

FIG. 2 shows a section of the electrical tool that has a counterpartcoding that fits the coding shown in FIG. 1, and

FIG. 3 shows a different counterpart coding of an electrical tool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a section of a plug-in battery pack 1 for an electricaltool that is not shown. The battery pack 1 has a grip 2 that a user canhold in order, for example, to withdraw it from a charging unit and toinsert its insertion region 3 into an electrical tool in the insertiondirection 4. The insertion region 3 has an end surface 6 thatconstitutes a bottom surface 8 and extends perpendicular to theinsertion direction 4. The end surface 6 is provided with a contact dome7. This contact dome 7 is situated eccentrically in relation to thebottom surface center 8′ of the battery pack 1. The contact dome 7extends essentially in the insertion direction 4. The contact dome 7 hasa top 9, which has an end surface 10 that extends parallel to the endsurface 6, i.e. perpendicular to the insertion direction 4, and hasoblique surfaces 11. The contact dome 7 has side surfaces 12 that extendperpendicular to the end surface 6 and the end surface 10. The endsurface 10 of the contact dome 7 is provided with two contact openings13 and 14 that contain electrical contacts 15. The contact dome 7 alsohas a mechanical coding 16, which cooperates with a counterpart codingof the electrical tool, not shown in FIG. 1, to form a coding system 30.The counterpart coding will be discussed in the description of FIG. 2.The mechanical coding 16 of the battery pack 1 has a recess 17. Therecess 17 has a rectangular bottom surface 31 that constitutes a recessbottom 32 of the recess 17. The recess 17 has a wall 18 that is composedof wall surface regions 19, 20, and 21. The wall 18 extends parallel tothe insertion direction 4. The wall surface regions 19 and 20 aresituated opposite from and parallel to each other. The wall surfaceregion 21 respectively extends at right angles to the wall surfaceregions 19 and 20. The side of the recess 17 opposite from the wallsurface region 21 is open at the edge, i.e. the recess 17 opens out ontoan outer wall surface 22 that constitutes one of the side surfaces 12 ofthe contact dome 7. It is also clear from FIG. 1 that the two opposingwall surface regions 19 and 20 have coding ribs 23 and 24 extending fromthem, which are situated opposite each other in an aligned fashion, withend surfaces 26 spaced apart from each other. This means that anintermediate space 27 is formed between the end surfaces 26. The codingribs 23 and 24 provide an improved coding measure of the recess 17. Therecess 17 is situated at least partially between the contacts 15. Theouter wall surface 22 has a rib 28 extending from it, which is likewisepart of the coding system 30, i.e. is part of the coding 16.Alternatively, it is also possible for such a rib 28 not to be provided(not shown).

FIG. 2 shows a section 35 of an electrical tool 36, which is otherwisenot shown, into which the battery pack 1 can be inserted. The insertionshaft that accommodates the battery pack 1 is not shown in FIG. 2. Thesection 35 of the electrical tool 36 has two contact tabs 37 thatcooperate with the contacts 15 when the battery pack 1 is in theinserted position. Through this connection, the battery pack 1 suppliesthe electrical energy to the electrical tool 36. The two contact tabs 37extend out from a base plane 38 of the electrical tool 36 on which acounterpart coding 39 of the coding system 30 is also situated. Uponinsertion of the battery pack 1, the counterpart coding 39 cooperateswith the coding 16 so that the battery pack can only be inserted if thecoding 16 and the counterpart coding 39 coincide.

The counterpart coding 39 has a projection 40 that has two wall surfaces41 situated opposite each other and 42 as well as an end surface 43 anda top surface 44. The projection 40 also has a waist 45 that is formedby two indentations 46 and 47 in the wall surfaces 41 and 42. Thedistance between the two wall surfaces 41 and 42 corresponds to thedistance between the wall surface regions 19 and 20 of the recess 17,with a very small amount of play taken into account. In addition, thedimensions of the indentations 46 and 47 correspond to the contours ofthe two coding ribs 23 and 24, also with a small amount of play takeninto account. This also affects the arrangement in such a way that whenthe coding 16 and counterpart coding 39 are put together, the region 48of the projection 40 on the other side of the waist 45 comes to restnext to the rib 28 of the coding 16. The projection 40 is adjoined by anL-shaped wall region 49 that has a leg 50 and a transverse leg 51.Between the transverse leg 51, the leg 50, and the region 48 of theprojection 40, an indentation 52 is formed, whose dimensions correspondto the dimensions of the rib 28 of the coding 16, taking into account acertain amount of play.

It is clear from the foregoing that as the battery pack 1 is beingattached to the electrical tool 36, the following coding function comesinto play: the projection 40 travels in a form-fitting fashion into therecess 17, in the process of which the two coding ribs 23 and 24 enterthe indentations 46 and 47 while the rib 28 enters the indentation 52.As has already been mentioned above, the coding function does notrequire the provision of a rib 28. Correspondingly, it is also possibleto eliminate the L-shaped wall region 49 in the counterpart coding 39.

If a battery pack 1 is used, whose coding 16 does not match the shape ofthe counterpart coding 39 of the electrical tool 36, e.g. because thedistance between the two wall surface regions 19 and 20 is smaller thanthe distance between the wall surfaces 41 and 42 of the projection 40,then the “forcing” known from the prior art is not possible, i.e. theprojection 40 and recess 17 cannot be pushed together even with the useof a very powerful force because a lateral deflection of the projection40 is not possible since the top surface 44 of the projection 40 wouldcome to rest on the recess edge region 53 of the coding 16 and thereforewould block a further insertion.

In order to increase the variety of permutations of the coding 16 andcounterpart coding 39, according to exemplary embodiments that are notshown, the two coding ribs 23 and 24 that a coding rib pair 55 extendout from the wall 18 of the recess 17 at correspondingly differentpositions. By contrast with the position shown in FIG. 1, the codingribs 23 and 24 can, for example, be situated closer to the wall surfaceregion 21 of the recess 17. In order to construct a permutation system,it is possible to provide a pattern of corresponding spacings for thevarious positions of the coding rib pair 55. By contrast with theembodiment shown in FIG. 1, it is thus also possible for the two codingribs 23 and 24 to not be aligned with each other, but instead to besituated slightly offset from each other so that their two end surfaces26 are situated only partially opposite each other. Alternatively or inaddition, it is also possible to provide additional coding ribs oradditional coding rib pairs. The structure of the projection is thenembodied in a corresponding fashion.

FIG. 3 shows an exemplary embodiment in which the projection 40 has forexample three waists 45, i.e. since the counterpart coding 39 is thusprovided with three indentations 46 and three indentations 47, thecoding 16, not shown, which is embodied in a form-fitting fashion inrelation to this, will therefore have three coding rib pairs 55. It isclear from all of the above that the coding system 30 thus producedpermits the implementation of a very large number of permutations.

1. A plug-in battery pack for an electrical tool, having a mechanicalcoding of a coding system for a cooperation with a mechanicalcounterpart coding of the coding system associated with the electricaltool, in which the coding extends in the insertion direction of thebattery pack, wherein the coding (16) has at least one recess (17) thatcooperates on opposite sides with at least one projection (40) that issituated on the tool and constitutes the counterpart coding (39),wherein the wall (18) of the at least one recess (17) has at least onecoding rib pair (55) extending out from it, whose coding ribs (23, 24)are situated diametrically opposite from each other in such a way thatthey at least partially overlap.
 2. The battery pack as recited in claim1, wherein the recess (17) has at least two wall surface regions (19,20) that are situated opposite each other in accordance with thethickness of the projection (40).
 3. The battery pack as recited inclaim 1, wherein the recess (17) is a recess (17) that is open at theedge.
 4. The battery pack as recited in claim 1, wherein the recess (17)has a single-cornered, multi-cornered, arc-shaped, and/or circularoutline structure.
 5. The battery pack as recited in claim 1, whereinthe recess (17) is situated in the vicinity of electrical contacts (15)of the battery pack (1).
 6. The battery pack as recited in claim 1,wherein the recess (17) is situated between at least two electricalcontacts (15) of the battery pack (1).
 7. The battery pack as recited inclaim 1, wherein the recess (17) is provided on a contact dome (7) ofthe battery pack (1).
 8. The battery pack as recited in claim 1, whereinthe recess (17) and/or a contact dome (7) is/are situated eccentricallyin relation to the bottom surface center (8′) of the battery pack (1).9. The battery pack as recited in claim 1, wherein at least one codingrib (23, 24) extends out from the wall (18) of the recess (17).
 10. Thebattery pack as recited in claim 1, wherein the coding rib (23, 24)extends out from the wall (18) of the recess (17) at a certain positionout of a plurality of different positions in order to produce variouspermutations.
 11. The battery pack as recited in claim 1, wherein therecess (17) that is open at the edge is adjoined by at least one outerwall surface (22) that is situated so that it faces a region of theprojection (40).
 12. A coding system for an electrical tool providedwith a plug-in battery pack, in particular as recited in claim 1, inwhich the battery pack has a mechanical coding, the electrical tool hasa mechanical counterpart coding, and the coding and counterpart codingextend in the insertion direction, wherein the coding (16) is embodiedas at least one recess (17), the counterpart coding (39) is embodied asat least one projection (40), and the coding (16) and counterpart coding(39) are matched to each other in a form-fitting fashion and engage ineach other when the battery pack (1) is in the inserted position. 13.The battery pack as recited in claim 1, wherein the at least one recess(17) is adjoined by at least one outer wall surface (22), and wherein acoding rib (28) extends from said at least one outer wall surface (22).